[RESOLVED] WinForms, making a Hotkey TextBox (capturing Ctrl + Alt + Letter)

[JuggaloBrotha]

Thanks for your perspective jmc, it was a nudge in the right direction.
I still had to use the KeyUp event to check if a modifier key had been released before a digit/letter key was pressed, want to visually show that to the user as it's happening.

This seems to work the way that I would like it to:

Public Class HotKeyTextBox
    Inherits System.Windows.Forms.TextBox
 
#Region " Variables "
 
    Private m_IsCtrl, m_IsAlt, m_IsShift As Boolean
    Private m_Char As Char = CChar(String.Empty)
    Private m_HasChar As Boolean
 
#End Region
#Region " Sub: New "
 
    Public Sub New()
        MyBase.New()
 
        m_IsCtrl = False
        m_IsAlt = False
        m_IsShift = False
        m_HasChar = False
    End Sub
 
#End Region
#Region " Overrides Subs: OnKeyDown, OnKeyUp "
 
    Protected Overrides Sub OnKeyDown(e As System.Windows.Forms.KeyEventArgs)
        e.SuppressKeyPress = True
 
        m_IsAlt = e.Alt
        m_IsCtrl = e.Control
        m_IsShift = e.Shift
 
        Select Case e.KeyCode
            Case Keys.ControlKey, Keys.ShiftKey, Keys.Menu
                'Ignore modifier keys alone.
            Case Else
                Dim ch As Char = Convert.ToChar(e.KeyCode)
                If Char.IsLetterOrDigit(ch) Then
                    m_Char = Char.ToUpper(ch)
                    m_HasChar = True
                End If
        End Select
 
        Call UpdateText()
        MyBase.OnKeyDown(e)
    End Sub
 
    Protected Overrides Sub OnKeyUp(e As System.Windows.Forms.KeyEventArgs)
        If Not m_HasChar Then
            m_IsAlt = e.Alt
            m_IsCtrl = e.Control
            m_IsShift = e.Shift
        End If
 
        Call UpdateText()
 
        If Not e.Alt AndAlso Not e.Control AndAlso Not e.Shift Then
            m_Char = CChar(String.Empty)
            m_HasChar = False
        End If
 
        MyBase.OnKeyDown(e)
    End Sub
 
    Private Sub UpdateText()
        Dim parts As New List(Of String)
 
        If m_IsCtrl Then parts.Add("Ctrl")
        If m_IsShift Then parts.Add("Shift")
        If m_IsAlt Then parts.Add("Alt")
        If m_HasChar Then parts.Add(m_Char.ToString)
 
        Me.Text = String.Join(" + ", parts)
    End Sub
 
#End Region
 
End Class